Self-aligning pitman bearing



April 22, 1930.A

R. R. BLOSS ET AL.

SELF ALIGNING PITMAN BEARING 2 Sheets-Sheet l Filed June '7, l1929 W ,mpg/KM Vd. 0 mwa n ,Hy A .nog PP R, n. BLOSS ET AL SELF ALIGNING PITMAN BEARING April 22,' 1930.

Filed June 7, 1929 2 Sheets-Sheet 2 RIJ 05a Y MQW M Ed. R Ww@ m E@ Patented' Apr. `2.2,"1930 A Y. UNTE STATES 7^Riel-IARD R. Bross' AND ROY o. PFEIL, or COLUMBUS, onto, YAssIciNoR's T oprnn INTERNATIONAL DERRICK aEQUrPMENT courrant?, or COLUMBUS, '01110, ANCOR- l lroRA'rIoN on oHIo Application led A.Tune 7,

-Our inventiony relates to a self-aligning pitman bearing and'is particularly adapted for use in connection with drilling and pumping mechanismL for oil, gas or artesian wells. lt is designed to meet a condition which frequently arisesfinjmechanism of this type owing to the more or less rough Conditions of will compensatey for misalignment by pivot- Ving the bearing at its base and maintaining a slidingcontact between the top ofthe cap section of the bearing'rand the wedge which is designed to'force this capy section downwardly. The diculty about this 'is that, if thev wedge is caused to exert suicient pressure Vto maintain the cap section in proper position to ensure satisfactory gripping ofthe wrist pin, the pressure exerted by this V,wedge must inevitably preclude such free sliding of the'cap section with relation tothe wedge as is necessary to properly compensate for misalignment. Conversely, if the wedge is forced in only to such extent asy will permit free sliding' of the cap section with relation. thereto as the bearing swingsabout its pivot Y to compensate for misalignment, the bearing sections will not beheld together with suticient firmness to avoid vlostmotion and consequent hammering of the wrist pin against the bearing surfaces of the bearing section. EvenV under the best conditions, the operation of, drilling 'or pumping is more or less jerkyr and the hammeringaction is'harmful enough without accentuatin'g this by permitting the bearing sections to loosely grip thewrist pin. w I, 'l 't Il We "have provided a self-aligning bearing for apitman'whe'rein the compensatory action of the bearing mainly take'splacelwithin itself, .In a bearing wherein the cap' section snLF-nnIoNING PITMAN isnaitiNe 1929. VSerial N0.*369,2024.

is held in position upon the base section by means vof a.wedge, we utilize a cap section which does not have a sliding contact with thejwedge but which hasyaolling contact about the topv part of the'wedge. This'will permit the cap section and wedge to move to affect compensation for misalignment with;- out thenecessity for diminishing such downward pressure upon lthe cap section as'rwill hold it firmly against the base section and the wrist pin.- ln addition, our cap sectionis so mounted that it is free to slide laterally along the wrist pin asthis wrist pin changes'its position due to misalignment. f

In conjunction with the cap section, we provide a base section for my bearing'which is slidably supported from beneath by means of an arcuate path of such a curvaturethat the bearingsurface of the bearing will revmain in lirm contact with the wrist pin as this f1,

wrist pin assumes various positions dueto misalignment. We preferablyl accomplish this by ymounting the lower section of the bearing slidably upon an arcuate track whose curvature is taken about a center within .that

portion of the wrst pin normally contained within the bearing. a f Stated another way, in specific application to a bearingwhose sections .are held together by a wedge, our bearing structure comprises v,

whose center of curvature is within the wrist 7.21,

in. It also ycomprises a cap section which is firmly held against the wrist pin by awedge exerting pressure thereon through a rolling contact which will permit the cap sectionto slide longitudinally withzrelationto the ywrist pin While remaining in intimate; and effective ,contact therewith, the pitman andgbearingffs'tructure being suchv as to ,permit this relatively'. slidin'ggaction.v Thus, itwilll he'l seen that we have provided abearinglv strucl ture in whichl the bearing sections are movable independei'itly with relation to eachother to compensate forfmisalignmentQwhile, in'addition, one of these sections is slidablewith relation-to the` wrist pinsothatadequate com- *c pensation may be affected while maintaining adequate pressure to hold the bearing sections in proper position, as bymeans of the rolling contact described..

The preferred embodiment of our invention is shown in the accompanying drawings wherein similar characters of reference designate corresponding parts and wherein: f

end of a pitman structure' with our self-aligning bearing mounted therein. Figure 4 is a vertical section of the structure shown in Figure 3. Y

y VFigure 5 isV aside elevation Vof the lower end Y of a pitman having oui` self-aligning bearingl forming apart thereof and illustrating the position assumed b-ythe bearing sections when oneV end of the wrist pin is tilted upwardly from a horizontal position.,

Figure 6 is a sectional view of the structure shown in Figure 5 and illustrating the bearing sections in the positions which they assume under the conditions illustrated by Figure 5. Y

Figure Z is a side elevation of the lower end ofthe pitman structure having our selfaligning bearing forming a Vpart thereof and illustrating the position assumed by the bearing sections when the opposite end of the wrist pin is tilted upwardly from a horizon` tal position.

Figure 8 is a sectional view of the structure shown in Figure 7 and illustrating the bearing sections the positions which they assume under the conditions illustrated by Figure 7.

Figure 9 is a section taken at right angles to; the sections shown in Figures 4, 6- and 8.

Referring' particularly to Figures 1 and 2 of' the drawings, it will be seen that the drilli rig structure shown embodies a Samson postl, a walking beam 2 and a temper screw 3 and pivotally `mounted upon the opposite end of the walking beam is a pitman 4; This pitman l1 is connected at its lower end to the wristjqiinfvv of a crank arm 6 carried upon a jack-post 7.

Referring particularly to Figure 2 of the drawings, the dotted line illustration; of the wrist'pin shows a conditionwhichfrequently arises either during theerection or' continued operationI of a structure of this type. In this condition, the wrist pin which should properly haveits axis'disposed in a horizontal plane is tilted in one direction or the other `so that its axis extends. upwardly lorl downwardly from the horizontal. Itis obvious that, in the event that the bearing structure which carries the wrist pin is rigidly connected to the pitman, a severe strain will be thrown upon the pitman. Efforts have been previously made to automatically compensate for this condition of misa'lignment but these efforts have been more or less ineffectual.

YVVe have provided a self-aligning bearing structure which automatically compensates for this condition of misalignment. In our bearing structure, the bearing is preferably mounted within the base of a U-shaped lower end of a pitman 8. The bearing structure7 itself, preferably7 comprises a substantially T-shaped member 9 having a central concavity 10 and spaced portions 11 and V12 of a trackr n ylhis track formed by the members 1.1 and 12 is adapted to slidably support the; arcuate lower surface 13 ofthe base section of our bearing. rlhis baser section is likewise provided with a downwardly Ventending portion lei which extends intothe central concavity 10 of the member 9 and is capable of a lateral movement therein. This downwardly eX- tending portion 14 is slotted as at 15 for the reception of a transverse pin 16 that extends through the side walls of the U-shaped member'of the pitman and assists in limiting the sliding action of the base section 13 upon the track 11 and 12. The slidingraction of this base section 13 upon the track 11 and 12 is also limited by means of downwardly extending flanges lcarried upon the base section 13. The upper surface of the base section 13 carries a semi-cylindrical concavity of proper bearing metal for supporting and embracingthe under side of the wrist pin 5.

The cap section of our Vbearing structure may vary as to form butit preferably comprises a body portion 18 with a concave under surface 19 and a concave bearing section 20 which is adapted to rest upon and closely lit the upper portion of the wrist pin 5. This body portion 19 is desirably provided with a slot 21 extending transverse thereof and having its bottom wall inclined from the horizontal with its upper wall substantially horizontal. A wedge 22 is adapted to be forced through slots inthe side walls of the pitman structure andthrough the slot 21 in such a way as to force the bearing cap downwardly upon the wrist pin. Y

It will be noted by reference to Figures 1, Band 6 of t-hedrawings that the side walls of this wedge member are substantially spaced from the side walls of the slots which are formed inthe walls of Vthe pitman. Furthermore, the upper edge of the wedgefme'm ber 22 is rounded and .is designed tobear upon the rounded upper walls of these slots in the side walls of the pitman with a rolling contact. rlhestructureris such that the wedge f member22 has a limited bearing upon the 'iin 'f structure, so that this wedge member may y with these upper walls of such slots without *,wristpin, a4 ase mounted to tilt withsaid m l-walls ofthe slots inthe pitman structure. It

l ing slots formed therein.

Y pitman comprising a base mounted to swing with the wrist pin asV it tilts, and a cap'mountswing laterally labout its points of contact materially diminishing the downward pressure which'is being exerted by the wedge upon the cap section. .In operation, as will might be notedfat this point that the walls of l the slots formed in. the legs of the kU-shaped member of the pitman structure are preferably reenfoiced by members 23 having align- If desired, the ,cap sections may be provided with a lubricant well 24 having an opening 25 and av flap-cover 26 therefor.' It may also be connected toa retractile spring 27 connected at its upper'end .to the pitman as at 28. Likewise, the pitman may be provided with a handle 29 and with a set screw 30 mounted in the cap section in such a manner as to permit of locking the wedge member at any desired point therein.

In operation, and referring particularly to Figures 3to 8inclusive, it will be seen that the tilting of the wrist pin, away from its Vnormal horizontal position will result inthe simultaneous tilting ofthe lower base section. Furthermore, itwill be apparent that' this simultaneous tilting of the base section will be effected without any separation lbetween the lower surface oft-he wrist pinand the bearing surface of the lower section, owing to the fact that the lower end of the base section slides upon its arcuate track and swings about a point within the wrist pin.

Furthermore, in this operation, the cap section of the bearing will swing independently of the base section, this swinging action being eected by rolling upon the upper surfaceof the wedge and being accompanied by a slidaction, the bearing surface of the cap section will remain in intimate contact with theupper surface lof thewrist pin throughout the tilting of the wrist pin.

The combined effect of thesefrelatively independent movements of the basefand cap sections is to cause the bearing surfaces of these two sections to hug lthe wrist pin throughout the tilting thereof and to accomplish this without any strainbeing applied` to the pitman, owing to the fact that both therbasesection and the cap section maintain pressure contact with the pitman-without being actually connected therewith. p

Having thus described our invention, what jwe claim is ing action longitudinallyof the wrist pin Due to this combined swinging yand sliding pin tilts.

2..A self-aligning bearing structure for a pitman com rising in combination with a wrist pin as said wrist pin tilts, and acap wrist pin tilts.

l ed to slide upon said wrist pin as said wrist y adapted to slide upon said wrist pin as said Y 3. A self-aligning kbearing structure for a lpitman comprising, in combination-with a wrist pin, a base mounted vto tilt with said wrist pin about a point kwithin said wrist pin as said wrist pin tilts, and a cap mounted to tilt upon said pitman and slide with relation to said wrist pin as said wrist pin tilts.

4.' A self-aligning bearing structure for a:

pitman comprising 'a base sectionand a cap section,said sections being mountedto slide along the wrist pin in opposite directions f mountedV to slide relative to the wrist pin y during such tilting action. 7. A selfealigning bearing structure comprising a base section, a cap section, a wedgey member for forcing said sections into intimate contact with a wristV pin, said wedge member being carried by one of said sections and having a rolling support upon said pitv man.

signatures. Y

RICHARD R. BLOSS.V ROY C. PFEIL.

1. A selfaligning bearing structure for a y In testimony whereof we hereby aiix our y 

